uthread_kern.c problems (still)

[Mac Newbold]

I've been getting bitten a lot lately by a bug in uthread_kern.c that
keeps causing my apache processes to run away, until I kill them. (dmesg
indicates it has also been happening to fstat processes too, but they die
instead of running away.)

The apache error log indicates this:

[Tue Mar 02 09:54:35 2004] [notice] child pid 52132 exit signal Abort trap (6)
Fatal error 'Unable to read from thread kernel pipe' at line 1100 in file
/usr/src/lib/libc_r/uthread/uthread_kern.c (errno = 0)

dmesg gets stuff like this:

pid 40525 (fstat), uid 0: exited on signal 11
pid 40377 (httpd), uid 80: exited on signal 6
pid 39306 (httpd), uid 80: exited on signal 6
pid 40770 (httpd), uid 80: exited on signal 6
pid 41064 (fstat), uid 0: exited on signal 11

I'm running apache2, mysql, php, and openssl:

Apache/2.0.48 (Unix) mod_perl/1.99_12 Perl/v5.6.1 PHP/4.3.4 mod_ssl/2.0.48
OpenSSL/0.9.7a Server

The crashes come most often running php scripts, and certain scripts can
be very reliable in causing the problem.

> uname -a
FreeBSD <host-name> 5.2-CURRENT FreeBSD 5.2-CURRENT #3: Thu Feb 26 17:50:22
MST 2004     root at tahiti.dmedia.ws:/usr/obj/usr/src/sys/GENERIC  i386

It started after I had been using 5.1-p10 for several months, so I
upgraded to the lastest current (post 5.2-RELEASE) a few days ago, and the
problem was still there.

Google reveals that people have been seeing crashes from it for at least 8
months now, going back to June 2003, most often with gnucash for some
reason, but with apache as well. Related messages:

http://lists.freebsd.org/pipermail/freebsd-hackers/2003-November/004121.html
http://lists.freebsd.org/pipermail/freebsd-current/2004-January/017764.html
http://lists.freebsd.org/pipermail/freebsd-gnome/2004-January/004505.html
http://lists.freebsd.org/pipermail/freebsd-ports/2003-June/002248.html
http://lists.freebsd.org/pipermail/freebsd-ports/2003-July/002839.html

I'm not on this list, so please keep me cc'd.

Any ideas for solutions or workarounds would be greatly appreciated.

If others are having this problem, and you'd like something to keep your
runaway processes under control, I've got a script for it now.

Thanks,
Mac

--
Mac Newbold
mac at macnewbold.com
MNE - Mac Newbold Enterprises, LLC
<a href="http://www.macnewbold.com/">MNE</a>
<a href="http://www.dmedia.ws/">Dmedia</a>
<a href="http://www.bluelune.com/">Bluelune</a>